An in-situ tissue sampling by means of chemical mass spectrum and gas chromatography analysis has been proposed by Dr. Vass at Oak Ridge Body Farm to determine the time after death. (See, e.g., U.S. Pat. No. 5,162,232 Vass.) There is a need to determine the timeline of death from a distance. In wars, many medics die while trying to save an already dead comrade, whether it is from getting caught in the middle of the fighting or from a baited body that contains hidden danger designed to create more injuries. Mass casualties and disasters in homeland security scenarios are also associated with contagious or radioactive hazardous conditions that may harm first responder medics (FRM) who are there to save the critically injured unstable people. FRMs must attend to those who would die without immediate medical attention and report to headquarters about what further resources are needed. This prevents FRMs from accomplishing their number one priority: save all the critically injured people. To attend to the time-sensitive injuries, FRMs must prioritize the order of which casualties they care for and minimize unproductive verification of death. In other words, the FRM does not want any potentially savable person to die while attending to someone who is already dead. Thus, knowing which casualties are already dead not only helps FRMs prioritize and maximize their medical expertise, it allows them to determine the total number of people who are alive and require attention by subtracting the number of deceased from the total number of bodies. This information helps the FRMs' second priority of informing headquarters of what additional rescue and medical supplies are needed. Based on these responsibilities, one of the current gaps appears to be that FRMs are unable to estimate death at a distance to avoid potentially deadly situations that may endanger their own safety. Such a distant decision-aid device with additional death determination capabilities may help FRMs better manage resources.
Dying is a process that varies over time. People who are alive have higher energy than deceased people. Physiological factors such as physical wellness and exertion create changes in the energy level over the living process. This leads to a much larger variance in energy fluctuation of living people relative to deceased people. Furthermore, the path each individual takes from a high energy life state to a low energy death state can vary drastically from person to person, causing a hysteresis loop. This phase transition phenomenon is analogous to a process in physics in which small magnetic domain walls re-adjust themselves under an increasing external magnetic field. As a result, the net magnetization varies, as does the dying process. In biology, the muscle response in lung tissue has demonstrated a hysteresis loop and people with chronic illnesses may get stuck in hysteresis with their health constantly cycling between high and low energy levels.
Some people may mistakenly declare death in the absence of detectable vital signs. This erroneous reasoning is due to the implicit bi-state assumption (if they are not alive, they are dead) and thus, negating the converse is not always right. In fact, there is a third category where a person who is not dead has no vital signs and these vitals can be restored with medical intervention, like resuscitation. Also, a person in a low energy state, e.g. comas, persistent vegetative states, or drug overdoses, may have feeble vital signs and are still alive, but in a unstable critical condition. This large variation of vitality signs may lead to false determinations of death. Thus, low energy indications of death are needed.
In nature, scavenger turkey vultures circulate over forests seeking dead rotten animals. How do birds locate, from above the forest trees, dead animals without seeing them? How do flies discover animals within minutes of death to lay fertilized eggs? They can smell death, which is known as peri-mortem (PM) odorants and which increases over time after death. The root cause of these volatile biomarker PM molecules is the cessation of white blood cell circulation, which leads to the buildup of bacterial byproducts. Bacteria proliferating without physiological inhibition and incomplete oxidation releasing reactive free radicals can break down large quantities of cellular tissues, releasing volatile byproducts in a PM plume around the body. Over time (days to years), PM molecules evolve into smaller post-mortem molecules, e.g. methyl mercaptan (CH3SH). Thus, mortem signs are defined, in this disclosure, as the full molecular spectrum of volatile biomarker molecules from peri-mortem to post-mortem.